Science Pick: Gut Microbiota and Environmental Chemicals in Diabetes and Obesity

Sarah Howard,
CHE Diabetes-Obesity Spectrum Working Group Coordinator

CHE’s January 19th call was on the interactions between gut microbiota and environmental chemicals in diabetes and obesity, a new area of research. Separately, gut microbiota and environmental chemicals may both contribute to the development of diabetes and obesity; what about the effects in combination?

The presenters reviewed research that shows that gut microorganisms can affect the absorption, distribution, metabolism, and elimination of environmental chemicals. For example, gut microbiota can cause a leaky gut, increasing absorption of chemicals. Gut microbes can modify polyaromatic hydrocarbons (PAHs) to turn them into estrogenic compounds. Microbiota can also affect detoxification processes in the liver.

An individual’s gut microbes may affect the rate at which they clear chemicals from their body. Seventy five percent of diabetogenic and obesogenic chemicals can be metabolized by gut microbes.

The interactions between gut microbiota and environmental chemicals may be significant not only for diabetes and obesity, but also for other diseases as well. It is a topic sure to see more research in the future.

To access slides and papers, visit the call page.

Early Puberty: Another Sign of Our (Chemical) Times?

Elise Miller, MEd

A major study released earlier this week in Pediatrics concluded that girls are starting puberty earlier than ever. (See the New York Times article or the full text of the study). Though early puberty is influenced by multiple and interacting factors, including heredity, socioeconomic status, obesity, premature birth, formula feeding and more, synthetic chemicals, particularly those that can disrupt our bodies’ normal hormonal messaging systems from conception onward, are increasingly considered contributors to this growing concern.

Controversy about whether earlier puberty was in fact happening was significantly heightened after a study suggesting similar findings was published in Pediatrics in 1997. However, questions about the association between chemical exposures and health problems from breast cancer to reproductive abnormalities can easily be dated back to the time of Rachel Carson’s research. Dr. Sandra Steingraber’s 2007 report, “The Falling Age of Puberty: What We Know, What We Need to Know,” commissioned by the Breast Cancer Fund, was based on a comprehensive review of the literature on the timing of puberty. Given the scientific evidence, the report recommended a set of actions—from improving the built environment to encourage physical activity to making healthy food more accessible to reducing the use of endocrine disrupting chemicals, such as phthalates and bisphenol A, in consumer products. What is notable about these recommendations is that they could curb not only the worrisome implications of earlier and earlier puberty, but a plethora of other chronic diseases and disabilities that currently plague our country.

Given it is far harder to turn an ocean liner around than a row boat, many leading thinkers underscore the need for creative solutions to be generated on the community level in order to develop effective, sustainable models. One such person is Wilma Subra, a leading resource scientist for low-income communities in the Gulf Coast. Michael Lerner will interview Dr. Subra on our CHE Partnership call tomorrow (visit the call page to RSVP). Other leaders emphasize that reforming our chemical regulatory system on a national level must be a priority. Action is also being taken along those lines with the introduction of “Toxic Chemicals Safety Act” in the House just late last month (see CHE’s Chemical Policy Reform webpage).

At whatever level you choose to approach this work, the study on early puberty published in Pediatrics this week only affirms that we, in fact, already know what we need to do. The harder part is how to do it—how to implement effective and strategic interventions at all these levels of society. As a CHE partner, we hope you will continue to participate in our calls and working groups to help us collectively figure out what we can do now to ensure that health is a birthright, not an afterthought.

The Cost of Toxic Exposures

Elise Miller, MEd

As the health care reform debate continues, little discussion has focused on the  significant cost savings that could be achieved through preventing exposures to toxic chemicals—chemicals that are shown to contribute to numerous health endpoints, including obesity, diabetes, learning and developmental disabilities, Parkinson’s, reproductive health problems, breast cancer, asthma and heart disease. When tobacco use was significantly curtailed, for example, the number of cases of lung cancer and others associated diseases fell dramatically, saving billions of dollars. The downside is that it took decades to persuade industry and government that the scientific data linking smoking and lung cancer was strong enough to warrant such strict regulation—and in the meanwhile, many, many more people became ill.

In this context, we have to ask how much evidence is enough before we switch to safer alternatives and implement regulations that allow only chemicals that have been thoroughly tested for human safety on the market? Do we have to wait years or even decades more, while people become increasingly sick, to reduce toxic exposures? What kind of health care savings might we have if we took preventive action now?

At a meeting of 150 scientists and physicians a couple weeks ago, Dr. Phil Landrigan, from Mount Sinai School of Medicine, stated that chronic childhood diseases linked to exposure to toxic chemicals in the environment have been surging upward, costing the US almost $55 billion a year. Other researchers in children’s environmental health say this number is, in fact, much higher. When you then add in the environmentally attributable fraction of health care costs related to a host of other chronic diseases and disabilities in adults, even conservative estimates suggest that our society could save almost $200 billion a year. 

Currently, the proposed health care reform bill in Congress suggests that the expansion of coverage would cost $829 billion over 10 years. Let’s say we could reduce environmental contributors to chronic disease and save $200 billion a year for 10 years. That would mean a total savings $2 trillion, thus making the current acrimonious debate regarding expanded coverage seem hardly worth it. In other words, if we invested in primary prevention—even in this relatively narrow arena of minimizing hazardous environmental exposures without addressing other pressing concerns such as socioeconomic status, access to health care, nutrition, etc., then full health-care coverage would fiscally achievable without dire predictions of bankrupting future generations.

Fortunately, EPA Administrator Lisa Jackson just announced some groundbreaking principles for establishing a system for testing chemicals that would be more protective of human health than current regulations are. She called on Congress to overhaul the woefully inadequate Toxic Substances Control Act, passed in 1976, that was supposed to regulate chemical manufacturing and use. In the past 30-plus years, only five chemicals out of the 80,000 now on the market were determined to put people at “unreasonable risk” under TSCA. Even asbestos, a substance well-studied and known to significantly impact human health, ultimately could not be banned given TSCA’s limited scope. By contrast, Jackson prescribed a new regulatory structure that would, among other features, promote green chemistry and safer alternatives and ensure manufacturers provide EPA with the necessary information to conclude that new and existing chemicals do not endanger public health or the environment (see the full EPA press release).

Now the question is whether Congressional leaders, embroiled in the politics of health care reform, can connect the dots and see that regulating chemicals to protect human health also means substantially reducing health care costs while increasing the capacity of the US to provide health care coverage to all its citizens. Surely that would be a  ‘win-win.’

Common Sense Steps

Frieda Slavin

Science is rarely certain about anything, and certainly not about most links between environmental exposures and health effects in people. Nonetheless, the evidence showing links to health grows ever stronger as research progresses and becomes ever-more sophisticated:

  • Scientists have generated compelling laboratory evidence revealing adverse effects in animals at low levels of exposure, affecting animal endpoints that are relevant to cancer, birth defects, reproductive effects, immune system dysfunctions, respiratory problems, learning and behavior problems, etc.
  • They have demonstrated that many of the underlying mechanisms causing those effects in animals are similar, if not identical, to human mechanisms.
  • They have documented human exposures to chemicals at levels that produce harm of many types in animals.
  • And they have identified trends in human health and disability that can be predicted on the basis of the above.

But establishing scientific certainty of harm to people is elusive at best and in many cases likely to be impossible before countless people would be affected adversely. After all, epidemiology can only establish harm after an epidemic has occurred. Purposefully carrying out controlled experiments on people is considered, appropriately, unethical. And thus we are left with the plethora of uncontrolled, largely unmonitored experiments currently underway because of ubiquitous exposure.

Given these limitations, and given that our current regulatory system is unlikely to strengthen exposure standards absent much firmer proof, what is a person, or a parent, or a family, to do?

Much good, practical advice is available on the web and in print. Some of the best places to turn for practical advice are listed below. In addition to pointing toward these resources, on this page we will highlight a few old themes (“constants”) and then focus on new issues that are emerging from recent research and analysis.

One general point: As you make choices about products to buy, things to do, food to eat, places to go, bear in mind that government standards for regulating environmental threats to health are at best a bare minimum and at worst completely inadequate and health threatening. So what you choose to do should always at least live up to those standards.

This is because government regulations represent a compromise negotiated between advocates for public health and parties, usually companies or trade associations, with an economic interest in protecting their access to the market. The playing field in which the negotiation takes place is strongly biased in favor of the vested interests, who have succeeded over several decades of lobbying to put in place evidentiary standards for proof of harm that make it very difficult to prevent marketing of new products, or removal of old, even in the face of compelling evidence of plausible harm. Decades of experience reinforce that conclusion.


  • Smoking harms adults, children and the developing fetus. It’s not just the irritation of the smoke itself, it’s also compounds added to the tobacco, the paper and the filter that make their way into your lungs and your bloodstream. Rules #1-3: don’t smoke; don’t inflict second-hand smoke on someone else; and don’t allow smokers to share their second-hand smoke with you or your family, especially your young children.
  • The fetus is remarkably sensitive to alcohol. Avoid alcoholic beverages during pregnancy. Otherwise impacts can last a lifetime.
  • Ozone damages developing lungs. While studies have shown for some time that ozone can trigger asthmatic attacks, the latest research even implicates ozone in the actual causation of asthma itself. When ozone levels rise and local governments issue air pollution warnings, pay attention. Some local newspapers carry regular ozone notices. They are worth reading and heeding.
  • Pollutants in some fish can damage the fetus, undermining development of disease resistance and cognitive development. Heed fish advisories posted by public health agencies.
    New York State Dept of Health: Health Advisories on Chemicals in Fish
  • Some plastics leach biologically-active materials into food with which they come into contact, particularly when heated. If you must use plastic, at least don’t microwave food in it.


Web and print resources

The Children’s Health Environmental Coalition’s HealtheHouse: an interactive resource for parents to learn about simple and effective steps they can take to protect their baby from environmental harm within the home.

The GreenGuide’s product reports: “a one-stop, reliable and easy-to-use shoppers’ guide so that you can make wiser, more conscientious shopping decisions.” Reports available include “flea control,” “insect repellant” and “household cleaning supplies.”

Raising Healthy Children in A Toxic World, a book by Philip Landrigan, Herbert Needleman and Mary Landrigan.

The Resource Guide on Children’s Environmental Health, by the Children’s Environmental Health Network.

Cleaning for Health: Products and Practices for a Safer Indoor Environment, an excellent and thorough review of cleaning products by Inform, Inc.

The Healthy School Network: ways to reduce exposures at school.

The Healthy Building Network: steps to reduce exposures via better selection of building materials and hospital equipment.

A number of organizations offer solid information about ways to reduce pesticide use. Among them:

Our Health and the Health of the Environment: How Are They Connected? What Can We Do to Improve Both?

The CHE Public Policy Primer

Webster’s defines a primer as a book of elementary principles or a book for teaching children how to read. The new CHE primer Our Health and the Health of the Environment: How Are They Connected? What Can We Do To Improve Both? aims at providing its readers with some elemental principles of environmental health.

Through the examples of asthma, learning disabilities and breast cancer, the primer explains what we are learning about the links between chronic illness, toxic chemicals and other environmental contaminants. The primer also gives examples of legislative and corporate policies aimed at improving our health and the health of the environment.

CHE Partners are encouraged to use the primer as part of discussions with elected officials or those running for public office. Printed copies are available free from CHE or a PDF version of primer may be downloaded.

Policies to Expand the Use of Health Tracking and Biomonitoring

Policies that Use Precaution to Make Decisions

Purchasing for Environmental Health

Creating a Chemicals Policy

Policies Championed by CHE Partners